Liposomes-enabled cancer chemoimmunotherapy.

Chemoimmunotherapy is an emerging paradigm in the clinic for treating several malignant diseases, such as non-small cell lung cancer, breast cancer, and large B-cell lymphoma. However, the efficacy of this strategy is still restricted by serious adverse events and a high therapeutic termination rate, presumably due to the lack of tumor-targeted distribution of both chemotherapeutic and immunotherapeutic agents. Targeted drug delivery has the potential to address this issue. Among the most promising nanocarriers in clinical translation, liposomes have drawn great attention in cancer chemoimmunotherapy in recent years. Liposomes-enabled cancer chemoimmunotherapy has made significant progress in clinics, with impressive therapeutic outcomes. This review summarizes the latest preclinical and clinical progress in liposome-enabled cancer chemoimmunotherapy and discusses the challenges and future directions of this field.

Bioactive nanocomposite hydrogel enhances postoperative immunotherapy and bone reconstruction for osteosarcoma treatment.

Osteosarcoma, a malignant bone tumor often characterized by high hedgehog signaling activity, residual tumor cells, and substantial bone defects, poses significant challenges to both treatment response and postsurgical recovery. Here, we developed a nanocomposite hydrogel for the sustained co-delivery of bioactive magnesium ions, anti-PD-L1 antibody (αPD-L1), and hedgehog pathway antagonist vismodegib, to eradicate residual tumor cells while promoting bone regeneration post-surgery. In a mouse model of tibia osteosarcoma, this hydrogel-mediated combination therapy led to remarkable tumor growth inhibition and hence increased animal survival by enhancing the activity of tumor-suppressed CD8+ T cells. Meanwhile, the implanted hydrogel improved the microenvironment of osteogenesis through long-term sustained release of Mg2+, facilitating bone defect repair by upregulating the expression of osteogenic genes. After 21 days, the expression levels of ALP, COL1, RUNX2, and BGLAP in the Vis-αPD-L1-Gel group were approximately 4.1, 5.1, 5.5, and 3.4 times higher than those of the control, respectively. We believe that this hydrogel-based combination therapy offers a potentially valuable strategy for treating osteosarcoma and addressing the tumor-related complex bone diseases.

Retrospective Analysis of Blood Biomarkers of Neurological Injury in Human Cases of Viral Infection and Bacterial Sepsis.

BACKGROUND: Blood biomarkers of neurological injury could provide a rapid diagnosis of central nervous system (CNS) injury caused by infections. An FDA-approved assay for mild traumatic brain injury (TBI) measures glial fibrillary acidic protein (GFAP) and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), which signal astrocyte and neuronal injury, respectively. Here, we assessed the applicability of this biomarker assay for determining infection-induced brain injury. METHODS: We measured serum levels of GFAP and UCH-L1 retrospectively in serum samples from three study populations: 1) human cases infected with Venezuelan equine encephalitis virus (VEEV) and Madariaga virus (MADV) (n = 73), 2) human sepsis patients who were severely ill or diagnosed with encephalitis (n = 66), and 3) sepsis cases that were subsequently evaluated for cognitive impairment (n = 64). RESULTS: In the virus infection group, we found elevated GFAP for VEEV (p = 0.014) and MADV (p = 0.011) infections, which correlated with seizures (p = 0.006). In the bacterial sepsis group, GFAP was elevated in cases diagnosed with encephalitis (p = 0.0007) and correlated with headaches (p = 0.0002). In the bacterial sepsis cases with a later cognitive assessment, elevated GFAP (p = 0.0057) at study enrollment was associated with cognitive impairment six months later with a positive prognostic capacity of 79% (CI: 66-95%; p = 0.0068). CONCLUSIONS: GFAP and UCH-L1 levels measured using an FDA-approved assay for TBI may indicate brain injury resulting from viral or bacterial infections and could predict the development of neurological sequelae.

Enhancing immunotherapy through PD-L1 upregulation: the promising combination of anti-PD-L1 plus mTOR inhibitors.

Immune checkpoint inhibitors (ICIs) targeting the programmed cell death protein 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) pathway have transformed urothelial cancer (UC) therapy. The correlation between PD-L1 expression and ICI effectiveness is uncertain, leaving the role of PD-L1 as a predictive marker for ICI efficacy unclear. Among several ways to enhance the efficacy of ICI, trials are exploring combining ICIs with serine/threonine-protein kinase mTOR (mTOR) inhibitors in different tumor types. The potential interaction between mTOR inhibitors and PD-L1 expression in UC has not been well characterized. In our study, we investigated how phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway inhibitors (TAK-228, everolimus and TAK-117) affect PD-L1 expression and function in preclinical bladder cancer cell models. TAK-228 increased cell surface levels of glycosylated PD-L1 in all but one of the seven cell lines, regardless of baseline levels. TAK-228 promoted the secretion of epidermal growth factor (EGF) and interferon-ß (IFNß), both linked to PD-L1 protein induction. Blocking EGF and IFNß receptors reversed the TAK-228-induced PD-L1 increase. Additionally, TAK-228 enhanced IFN-γ-induced PD-L1 expression and intracellular HLA-I levels in some cells. TAK-228-treated bladder cancer cells exhibited resistance to the cytotoxic effects of peripheral blood mononuclear cells (PBMCs) and cluster of differentiation 8 (CD8)+ T cells. The addition of an anti-PD-L1 antibody diminished this resistance in T24 cells. Increased expression of PD-L1 under TAK-228 exposure was confirmed in patient-derived explants (PDEs) treated ex vivo. These preclinical findings suggest that mTOR inhibition with TAK-228 can increase PD-L1 levels, potentially impacting the specific immune response against UC cells. This highlights the rationale for exploring the combination of mTOR inhibitors with ICIs in patients with advanced UC.

Efficacy of PD-1 or PD-L1 inhibitors for the therapy of cervical cancer with varying PD-L1 expression levels: a single-arm meta-analysis.

Objective: To assess the effectiveness and tolerability of both PD-1 and PD-L1 inhibitors in advanced cervical cancer (CC), focusing on varying PD-L1 levels. Methods: A comprehensive exploration was carried out on EMBASE, PubMed, Cochrane Library databases as well as Web of Science up to May 25, 2024, for studies involving advanced CC patients receiving PD-1/PD-L1 inhibitors. Inclusion criteria were studies reporting objective response rate (ORR), disease control rate (DCR), median progression-free survival (PFS), as well as median overall survival (OS). Data extraction and quality assessment were performed by two reviewers using the JBI Case Series Critical Appraisal Checklist, followed by a meta-analysis via STATA/MP 16.0. Results: Five eligible studies comprising 223 patients were chosen. ORR and DCR were 42% (95% CI: 17%-66%, P = 0.00) and 70% (95% CI: 22%-117%, P = 0.00), respectively, in the PD-L1 positive patients and were 36% (95% CI: 17%-54%, P = 0.00) and 47% (95% CI: 30%-63%, P = 0.00), respectively, in patients with PD-L1 negativity. For patients exhibiting PD-L1 positivity, median PFS and median OS were 3.98 months (95% CI: 0.80-7.16, P = 0.01) and 11.26 months (95% CI: 3.01-12.58, P = 0.00), respectively. Conclusion: With PD-1/PD-L1 inhibitors, PD-L1 positive CC patients demonstrate superior ORR, DCR, median PFS, and median OS, underscoring PD-L1 as one biomarker for immunotherapy response.

Development and Characterization of an Anti-PD-L1 Immunotoxin for Targeted Cancer Therapy.

BACKGROUND: Immunotoxins (ITs) represent a novel class of therapeutics with bifunctional structures that facilitate their penetration through cell membranes to induce target cell destruction. Programmed cell death ligand-1 (PD-L1), a human cell surface protein, is overexpressed in various cancers. This study aimed to construct a novel IT by genetically fusing an anti-PD-L1 Nanobody (Nb) to a truncated diphtheria toxin (DT). METHODS: The IT construct comprised a 127-amino acid anti-PD-L1 Nb fused to a 380-amino acid fragment of DT, with an N-terminal 6x-His tag. Molecular cloning techniques were employed, followed by transformation and verification through colony-PCR, enzyme digestion, and sequencing. The anti-PD-L1 Nb was expressed in WK6 E. coli cells induced by Isopropyl ß-D-1- Thiogalactopyranoside (IPTG) and purified from periplasmic extracts using immobilized Metal Ion Affinity hromatography (IMAC). The IT was similarly expressed, purified, and validated via SDS-PAGE and Western blot analysis. RESULTS: ELISA confirmed the binding activity of both Nb and IT to immobilized PD-L1 antigen, whereas truncated DT exhibited no binding. MTT assays demonstrated significant cytotoxicity of IT on A-431 cell lines compared to Nb and truncated DT controls. Statistical analyses underscored the significance of these findings. CONCLUSION: This study provides a thorough characterization of the constructed IT, highlighting its potential as a therapeutic agent targeting PD-L1-expressing cancer cells. The results support the potential of this IT in cancer immunotherapy, emphasizing the need for further investigation into its efficacy and safety profiles.

The European Larynx Organ Preservation Study [MK-3475-C44].

The European Larynx Organ Preservation Study (ELOS; NCT06137378) is a prospective, randomized, open-label, two-armed parallel group controlled, phase II multicenter larynx organ preservation (LOP) trial in locoregionally advanced (LA) stage III, IVA/B head and neck squamous cell carcinoma of the larynx or hypopharynx (LHSCC) amenable for total laryngectomy (TL) with PD-L1 expression within tumor tissue biopsy, calculated as CPS ≥ 1. Induction chemotherapy (IC) with docetaxel and cisplatin (TP) followed by radiation will be compared to TP plus PD-1 inhibition by pembrolizumab (MK-3475; 200 mg i.v. starting day 1 q3w for 17 cycles). After a short induction early response evaluation (ERE) 21 ± 3 days after the first cycle of IC (IC-1), responders achieving endoscopic estimated tumor surface shrinkage (ETSS) ≥30% will get an additional two cycles of IC followed by intensity-modulated radiotherapy 70-72 Gy (EQD2/α/ß = 10) aiming at LOP. Nonresponders (ETSS < 30% or progressing disease) will receive TL and bilateral neck dissection followed by postoperative radiation or chemoradiation as recommended by the clinic's multidisciplinary tumor board. Pembrolizumab treatment will be continued in the intervention arm regardless of ETSS status after IC-1 in both responders and laryngectomized nonresponders, independent of subsequent decisions on adjuvant therapy after TL. Clinical Trial Registration: clinicaltrials.gov, identifier NCT06137378.

Ipilimumab and nivolumab plus radioembolization as salvage therapy for atezolizumab and bevacizumab refractory hepatocellular carcinoma resulting in complete pathologic response.

Unresectable hepatocellular carcinoma unresponsive to first-line immunotherapy has a poor prognosis with modest response to tyrosine kinase inhibitors in the second line. In these patients, the benefit of local therapy with immunotherapy rechallenge is unknown. Radioembolization is a guideline-supported locoregional therapy for HCC that has shown the potential for synergy in combination with immunotherapy. This report describes a patient with veno-invasive HCC and extrahepatic invasion of the right kidney which progressed on atezolizumab and bevacizumab and was subsequently downstaged to resection with ipilimumab and nivolumab plus radioembolization yielding a complete pathologic response. The patient is currently more than 2 years since diagnosis without evidence of disease recurrence.

Upregulation of NFE2L1 reduces ROS levels and α-synuclein aggregation caused by GBA1 knockdown.

Biallelic mutations in the GBA1 gene result in Gaucher disease (GD), and both patients with GD and carriers of a single GBA1 mutation have an increased susceptibility to Parkinson's disease (PD), but the underlying mechanisms of this association are not yet clear. In previous studies, we established Gba1 F213I point mutation mice and found that homozygous Gba1 F213I mutant mice died shortly after birth, while heterozygous mice could survive normally. In this study, we investigated the transcriptomic changes in the brain tissue of Gba1 F213I heterozygous mice, identifying 138 differentially expressed genes. Among them, Nfe2l1 was the most significantly downregulated gene. Inhibition or knockdown of GBA1 in BE(2)-M17 cells resulted in decreased expression levels of NFE2L1. Knockdown of GBA1 or NFE2L1 could lead to an elevation in intracellular aggregation of α-synuclein (α-syn) and reactive oxygen species (ROS) levels, while upregulation of NFE2L1 effectively mitigated those cellular manifestations induced by GBA1 knockdown. In summary, our in vitro results showed that upregulation of NFE2L1 may provide a therapeutic benefit for cellular phenotypes resulting from GBA1 knockdown, providing new insights for future research on GD and GBA1-associated PD.

CD68 positive and/or CD163 positive tumor-associated macrophages and PD-L1 expression in breast phyllodes tumor.

INTRODUCTION: PD-L1 expression and tumor-associated macrophage (TAM) status in phyllodes tumors (PT) have only been examined in a limited number of studies. This study aimed to investigate the expression of PD-L1 and TAM in breast PT and examine their implications. METHODS: Tissue microarrays were constructed from 181 PT samples, and immunohistochemistry for PD-L1 antibodies (SP142, SP263, and 22C3) and TAM markers (CD68 and CD163) were performed. The staining results were compared and analyzed with clinicopathological parameters. RESULTS: Of the 181 samples, 149 were benign, 27 were borderline, and five were malignant. The number of CD68- and/or CD163-positive TAMs increased with increasing PT grades (P < 0.001), and the number of CD68-positive TAMs was significantly positively correlated with that of CD163-positive TAMs (R = 0.704, P < 0.001). Some of the CD68- and/or CD163-positive cells exhibited positivity for actin staining, displaying hybrid characteristics that resemble both histiocytes and myofibroblasts. PD-L1 SP263 tumor cells and PD-L1 SP263 immune cells were the most expressed in malignant PTs (P < 0.001). The number of CD68- and/or CD163-positive TAMs increased when PD-L1 SP263 immune cells were expressed (P < 0.001). The number of CD68- and/or CD163-positive TAMs was positively correlated with PD-L1 22C3 immune cells (R = 0.299, P < 0.001 and R = 0.336, P < 0.001, respectively). Univariate analysis showed that PD-L1 SP263 immune cell expression (P = 0.016) was associated with shorter disease-free survival and that PD-L1 22C3 tumor cell expression (P < 0.001) was associated with shorter overall survival. CONCLUSION: The number of CD68- and/or CD163-positive cells increases with increasing PT histological grade, and these cells exhibit hybrid characteristics, resembling both histiocyte and myofibroblasts.

Immunotherapy in Head and Neck Cancer: Treatment Paradigms, Future Directions, and Questions.

The use of immunotherapy in head and neck squamous cell carcinoma (HNSCC)has increased treatment options for patients who may not be candidates for traditional cytotoxic chemotherapy. Recent studies have resulted in the approval of immunotherapy in the first and second line setting for recurrent/metastatic disease. Various combinations of immunotherapy with targeted therapies, monoclonal antibodies, or human papilloma virus vaccines are also being studied in recurrent/metastatic disease. Currently, programmed death-ligand 1 status is the main marker utilized to assess potential response to immunotherapy. Studies are focused on identifying additional markers, which may help better predict response to immunotherapy for HNSCC patients.

On the interface of aging, cancer, and neurodegeneration with SIRT6 and L1 retrotransposon protein interaction network.

Roles of the sirtuins in aging and longevity appear related to their evolutionarily conserved functions as retroviral-restriction factors. Retrotransposons also promote the aging process, which can be reversed by the inhibition of their activity. SIRT6 can functionally limit the mutation activity of LINE-1 (L1), a retrotransposon causing cancerogenesis-linked mutations accumulating during aging. Here, an overview of the molecular mechanisms of the controlling effects was created by the pathway enrichment and gene function prediction analysis of a protein interaction network of SIRT6 and L1 retrotransposon proteins L1 ORF1p, and L1 ORF2p. The L1-SIRT6 interaction network is enriched in pathways and nodes associated with RNA quality control, DNA damage response, tumor-related and retrotransposon activity-suppressing functions. The analysis also highlighted sumoylation, which controls protein-protein interactions, subcellular localization, and other post-translational modifications; DNA IR Damage and Cellular Response via ATR, and Hallmark Myc Targets V1, which scores are a measure of tumor aggressiveness. The protein node prioritization analysis emphasized the functions of tumor suppressors p53, PARP1, BRCA1, and BRCA2 having L1 retrotransposon limiting activity; tumor promoters EIF4A3, HNRNPA1, HNRNPH1, DDX5; and antiviral innate immunity regulators DDX39A and DDX23. The outline of the regulatory mechanisms involved in L1 retrotransposition with a focus on the prioritized nodes is here demonstrated in detail. Furthermore, a model establishing functional links between HIV infection, L1 retrotransposition, SIRT6, and cancer development is also presented. Finally, L1-SIRT6 subnetwork SIRT6-PARP1-BRCA1/BRCA2-TRIM28-PIN1-p53 was constructed, where all nodes possess L1 retrotransposon activity-limiting activity and together represent candidates for multitarget control.

Cancer-associated fibroblasts-derived exosomal ZNF250 promotes the proliferation, migration, invasion, and immune escape of hepatocellular carcinoma cells by transcriptionally activating PD-L1.

Hepatocellular carcinoma (HCC) is a lethal form of liver cancer, and the tumor microenvironment, particularly cancer-associated fibroblasts (CAFs), plays a critical role in its progression. This study aimed to elucidate the mechanism by which CAF-derived exosomes regulate the development of HCC. The study employed quantitative real-time polymerase chain reaction for mRNA expression analysis and western blot analysis for protein expression detection. Chromatin immunoprecipitation assay and dual-luciferase reporter assay were performed to investigate the relationship between zinc finger protein 250 (ZNF250) and programmed cell death 1 ligand 1 (PD-L1). Transmission electron microscopy and western blot analysis were used to characterize the isolated exosomes. The transferability of CAF-derived exosomes and normal fibroblasts (NFs)-derived exosomes into HCC cells was analyzed using a green fluorescent labeling dye PKH67. Cell proliferation was assessed via a 5-Ethynyl-2'-deoxyuridine assay, while Transwell assays were conducted to evaluate cell migration and invasion. Flow cytometry was performed to measure cell apoptosis, while enzyme-linked immunosorbent assays were used to assess the levels of tumor necrosis factor-α and perforin. Finally, a xenograft mouse model was constructed to examine the effects of exosomes derived from ZNF250-deficient CAFs on the tumor properties of HCC cells. The study revealed increased expression of ZNF250 in HCC tissues and cells, with ZNF250 transcriptionally activating PD-L1 in HCC cells. ZNF250 expression was associated with HbsAg, clinical stage and tumor size of HCC patients. CAF-derived exosomal ZNF250 can regulate PD-L1 expression in HCC cells. Furthermore, exosomes derived from ZNF250-deficient CAFs inhibited the proliferation, migration, invasion, and immune escape of HCC cells by downregulating PD-L1 expression. Moreover, CAF-derived exosomal ZNF250 promoted tumor formation in vivo. These findings provide insights into the role of CAF-derived exosomes in the suppression of HCC development, highlighting the significance of ZNF250 and PD-L1 regulation in tumor progression.

Efficacy of durvalumab plus chemotherapy in advanced biliary duct cancer and biomarkers exploration.

BACKGROUND: The anti-PD-L1 antibody durvalumab has been approved for use in first-line advanced biliary duct cancer (ABC). So far, predictive biomarkers of efficacy are lacking. METHODS: ABC patients who underwent gemcitabine-based chemotherapy with or without durvalumab were retrospectively enrolled, and their baseline clinical pathological indices were retrieved from medical records. Overall (OS) and progression free survival (PFS) were calculated and analyzed. The levels of peripheral biomarkers from 48 patients were detected with assay kits including enzyme-linked immunosorbent assay. Genomic alterations in 27 patients whose tumor tissues were available were depicted via targeted next-generation sequencing. RESULTS: A total of 186 ABC patients met the inclusion criteria between January 2020 and December 2022 were finally enrolled in this study. Of these, 93 patients received chemotherapy with durvalumab and the rest received chemotherapy alone. Durvalumab plus chemotherapy demonstrated significant improvements in PFS (6.77 vs. 4.99 months; hazard ratio 0.65 [95% CI 0.48-0.88]; P = 0.005), but not OS (14.29 vs. 13.24 months; hazard ratio 0.91 [95% CI 0.62-1.32]; P = 0.608) vs. chemotherapy alone in previously untreated ABC patients. The objective response rate (ORR) in patients receiving chemotherapy with and without durvalumab was 19.1% and 7.8%, respectively. Pretreatment sPD-L1, CSF1R and OPG were identified as significant prognosis predictors in patients receiving durvalumab. ADGRB3 and RNF43 mutations were enriched in patients who responded to chemotherapy plus durvalumab and correlated with superior survival. CONCLUSION: This retrospective real-world study confirmed the clinical benefit of durvalumab plus chemotherapy in treatment-naïve ABC patients. Peripheral sPD-L1 and CSF1R are promising prognostic biomarkers for this therapeutic strategy. Presence of ADGRB3 or RNF43 mutations could improve the stratification of immunotherapy outcomes, but further studies are warranted to explore the underlying mechanisms.

Inverse correlation between TP53 gene status and PD-L1 protein levels in a melanoma cell model depends on an IRF1/SOX10 regulatory axis.

BACKGROUND: PD-L1 expression on cancer cells is an important mechanism of tumor immune escape, and immunotherapy targeting the PD-L1/PD1 interaction is a common treatment option for patients with melanoma. However, many patients do not respond to treatment and novel predictors of response are emerging. One suggested modifier of PD-L1 is the p53 pathway, although the relationship of p53 pathway function and activation is poorly understood. METHODS: The study was performed on human melanoma cell lines with various p53 status. We investigated PD-L1 and proteins involved in IFNγ signaling by immunoblotting and mRNA expression, as well as membrane expression of PD-L1 by flow cytometry. We evaluated differences in the ability of NK cells to recognize and kill target tumor cells on the basis of p53 status. We also investigated the influence of proteasomal degradation and protein half-life, IFNγ signaling and p53 activation on biological outcomes, and performed bioinformatic analysis using available data for melanoma cell lines and melanoma patients. RESULTS: We demonstrate that p53 status changes the level of membrane and total PD-L1 protein through IRF1 regulation and show that p53 loss influences the recently discovered SOX10/IRF1 regulatory axis. Bioinformatic analysis identified a dependency of SOX10 on p53 status in melanoma, and a co-regulation of immune signaling by both transcription factors. However, IRF1/PD-L1 regulation by p53 activation revealed complicated regulatory mechanisms that alter IRF1 mRNA but not protein levels. IFNγ activation revealed no dramatic differences based on TP53 status, although dual p53 activation and IFNγ treatment confirmed a complex regulatory loop between p53 and the IRF1/PD-L1 axis. CONCLUSIONS: We show that p53 loss influences the level of PD-L1 through IRF1 and SOX10 in an isogenic melanoma cell model, and that p53 loss affects NK-cell cytotoxicity toward tumor cells. Moreover, activation of p53 by MDM2 inhibition has a complex effect on IRF1/PD-L1 activation. These findings indicate that evaluation of p53 status in patients with melanoma will be important for predicting the response to PD-L1 monotherapy and/or dual treatments where p53 pathways participate in the overall response.

HDAC1 promotes basal autophagy and proliferation of colorectal cancer cells by mediating ATG16L1 deacetylation.

Autophagy is an evolutionarily conserved degradation pathway for maintaining cellular homeostasis and its dysregulation leads to numerous human diseases such as cancer. As a core protein for autophagy, ATG16L1 (autophagy related 16 like 1) is heavily regulated by post-translational modifications, including phosphorylation, ubiquitination, and methylation, which is critical for autophagy regulation. In this study, we identify HDAC1 (histone deacetylase 1) as a regulator of ATG16L1 acetylation and hence autophagy. Specifically, HDAC1 colocalizes and interacts with ATG16L1, and reduces its acetylation, which is highly dependent on its enzymatic activity. By promoting ATG16L1 deacetylation, HDAC1 enhances ATG16L1 interaction with the ATG12-ATG5 conjugate, resulting in the activation of autophagic pathway. Consistently, the induction of basal autophagy by HDAC1 in colorectal cancer cells largely relies on its deacetylase activity as well as ATG16L1. Moreover, HDAC1 enhances the survival, proliferation, and transformation of colorectal cancer cells in an ATG16L-dependent manner, indicating the fundamental roles of autophagy in colorectal cancer. Together, our findings uncover a novel regulatory mechanism of autophagy and suggest both HDAC1 and ATG16L1 as therapeutic targets for colorectal cancer.

Comparison of PD-L1 assays in head and neck carcinoma.

Programmed cell death-ligand 1 (PD-L1) expression is a predictive biomarker for response to immune checkpoint inhibitor in head and neck squamous cell carcinoma. Given the range of antibodies and platforms for PD-L1 testing, it is essential to understand the performance of different staining and scoring methods. PD-L1 expression in 156 head and neck mucosal squamous cell carcinoma (HNmSCC) cases at Asan Medical Center was assessed using 106 tissue microarray (TMA) cores and 50 whole slides. Three standardised PD-L1 assays (22C3 pharmDx, SP263, and 28-8 pharmDx) and one laboratory-developed test (22C3 LDT) were evaluated: the combined positive score (CPS) with ≥1, ≥20, and ≥50 cut-offs, and the tumour positive score (TPS) with ≥1%, ≥20%, ≥50% cut-offs. Concordance on a continuous scale among the assays was good to excellent for CPS [intraclass correlation coefficient (ICC) range 0.73-0.94] and TPS (ICC range 0.70-0.94) and in both TMA and whole slides cohorts. Stratification by variable cut-offs demonstrated moderate to good agreement among most assays, as analysed by Gwet's AC1. PD-L1 expression was significantly correlated with tumour location using the 22C3 pharmDx assay (CPS, p=0.014; TPS, p=0.033). Notable concordance was found among PD-L1 assays, suggesting their potential interchangeability in HNmSCC.

Colorectal Cancer-Derived Exosomes Impair CD4+ T Cell Function and Accelerate Cancer Progression via Macrophage Activation.

Background: Exosomal programmed death ligand 1 (PD-L1), an exosomal membrane protein found in many tumor types, is reckoned to help regulate the immune microenvironment. However, the functions and the mechanisms underlying the exosome-mediated regulation of the immune microenvironment in colorectal cancer (CRC) remain unknown. Methods: Western blotting was used to investigate the levels of exosomal PD-L1 in the peripheral blood of patients with CRC and healthy controls. A CRC mouse model was constructed by administering 10 mg/kg azoxymethane (AOM) and dextrane sodium sulfate (DSS) intraperitoneally. The mice were then administered the control or CRC-derived exosomes to examine the regulatory effect of the exosomes on macrophage infiltration and CRC development. In vitro studies, using a coculture system, and flow cytometry analysis were conducted to examine the relationship between the regulatory effect of CRC-derived exosomes on CD4+ T cells and tumor-associated macrophages. RNA-seq and reverse transcription-quantitative polymerase chain reaction assays were used to investigate the mechanisms underlying the regulatory effect of the CRC-derived exosomes on macrophage proliferation and the regulation of the immune microenvironment during CRC development. Results: In patients with CRC, higher levels of exosomal PD-L1 were associated with a more severe form of disease. The treatment of mice with AOM/DSS-induced CRC with CRC-derived exosomes resulted in high levels of macrophage proliferation, increased PD-L1 levels in macrophages, and accelerated CRC progression. Importantly, analysis of an in vitro coculture system and flow cytometry analysis showed that the CRC-derived exosomes transported PD-L1 into macrophages and impaired CD4+ T cell function. Preliminary data suggest that the NF-κb signaling pathway regulates the function of CRC-derived exosomal PD-L1-dependent macrophages. Conclusion: CRC-derived exosomes induce the proliferation of macrophages and increase their PD-L1 levels. They also impair CD4+ T cell function and promote CRC progression. Our findings reveal a novel exosomal PD-L1-mediated crosstalk between the CRC cells and immune cells in the CRC microenvironment.

Parthenolide Inhibits Synthesis and Promotes Degradation of Programmed Cell Death Ligand 1 and Enhances T Cell Tumor-Killing Activity.

Parthenolide is a germacrane sesquiterpene lactone separated from the traditional medicinal plant feverfew. Previous studies have shown that parthenolide possesses many pharmacological activities, involving anti-inflammatory and anticancer activities. However, the antitumor mechanism of parthenolide has not been fully elucidated. Thus, we investigate the potential antitumor mechanisms of parthenolactone. We predicted through network pharmacology that parthenolide may target HIF-1α to interfere with the occurrence and development of cancer. We found that parthenolide inhibited PD-L1 protein synthesis through mTOR/p70S6K/4EBP1/eIF4E and RAS/RAF/MEK/MAPK signaling pathways and promoted PD-L1 protein degradation through the lysosomal pathway, thereby inhibiting PD-L1 expression. Immunoprecipitation and Western blotting results demonstrated that parthenolide inhibited PD-L1 expression by suppressing HIF-1α and RAS cooperatively. We further proved that parthenolide inhibited cell proliferation, migration, invasion, and tube formation via down-regulating PD-L1. Moreover, parthenolide increased the effect of T cells to kill tumor cells. In vivo xenograft assays further demonstrated that parthenolide suppressed the growth of tumor xenografts. Collectively, we report for the first time that parthenolide enhanced T cell tumor-killing activity and suppressed cell proliferation, migration, invasion, and tube formation by PD-L1. The current study provides new insight for the development of parthenolide as a novel anticancer drug targeting PD-L1.

SOX13-mediated transcription of LRP11 enhances malignant properties of tumor cells and CD8+ T cell inactivation in breast cancer through the ß-catenin/PD-L1 axis.

BACKGROUND: High expression of low-density lipoprotein receptor related protein 11 (LRP11) has been associated with unfavorable prognosis of breast cancer (BC). This study explores the exact roles of LRP11 in BC progression and investigates the associated mechanism. METHODS: LRP11 expression in BC tissues and cells was determined by immunohistochemistry or RT-qPCR. LRP11 upregulation was induced in two human BC cell lines to investigate its impact on cell proliferation, migration, and invasion. Its regulation on immune activity was assessed by detecting PD-L1 protein levels and generating a co-culture system of cancer cells and CD8+ T cells. Mouse allograft tumor models were generated to analyze the function of LRP11 in tumorigenesis and immune activity in vivo. Gain-of-function assays of SRY-box transcription factor 13 (SOX13) were performed to investigate its function in development and immunosuppression of BC. RESULTS: LRP11 was found to be highly expressed in BC tissues and cells, presenting an association with unfavorable prognosis of patients. Artificial upregulation of LRP11 in BC cells triggered malignant properties of cells, enhancing ß-catenin-mediated transcriptional activation of PD-L1, thus decreasing immune activity of the co-cultured CD8+ T cells. Consistently, LRP11 upregulation in mouse 4 T1 cells and promoted tumorigenesis and immune evasion in mice. SOX13 was found to bind the LRP11 promoter for transcriptional activation. Upregulation of SOX13 similarly promoted growth of BC cells and immunosuppression, with its oncogenic effects blocked by the additional LRP11 knockdown. CONCLUSION: This study demonstrates that SOX13 is responsible for LRP11 transcription activation, leading to increased malignant phenotype of BC cells and diminished activity CD8+ T cells. This evidence highlights SOX13 and LRP11 as promising novel therapeutic targets to reduce malignant phenotype of BC cells and overcome immunosuppression.